Published in Scientific Papers. Series D. Animal Science., Vol. LVI Written by Nadezhda PETKOVA, Panteley DENEV

The current research aimed to present the evaluation of the underground parts of two widespread plants in Bulgaria - prickly lettuce (Lactuca serriola L.) and annual sow thistle (Sonchus oleraceus L.) as a source of inulin-type fructans. The sequential ethanol and water extractions from their dry taproots were carried out. The amount of extracted fructans was defined by the resorcinol assay. The fructooligosacharides and inulin contents of the obtained extracts were analyzed by TLC and HPLC-RID methods. The total fructan content in the weed plant Sonchus oleraceus L. (19.6% dw) is higher than the fructan level in the roots of Lactuca serriola L (9.56% dw). In the ethanol extracts were observed the presence of monosaccharide glucose and fructose, high level of sucrose and trisaccharides 1-kestose. In the result of the carried analysis, we can conclude that the roots are rich source of fructans as the fructoligosacharides fraction dominates in ethanolic extracts. These plants could not only be consider as weeds, but it have to pay attention to their future possibility to be used as a potential source of fructooligosacharides with prebiotic effect in nutrition formula for animals and human.